Sony HKDV-900, Maintenance Manual

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2-18 (E)
HKDV-900
2-3-8. Troubleshooting for 7SEG LED Test Error
The display does not appear properly
2-3-9. Troubleshooting for Switch Test Error
The LED does not light even if the button is pressed
2-3. Troubleshooting
Is the harness between CN401 (A-3) on the
CP-364 and CN2 (A-1 : B side) on the
CP-365 boards properly connected?
Connect harness connector properly and
recheck them
OK
Is WR signal of control ICs (IC308 (F-2) and
IC310 (F-2) on the CP-364 board) proper?
NG
NG
OK
Connection defect between IC200 (G-1),
IC308 and IC310 on the CP-364 board
OK
Is output signal (ON : + 3 V to + 4 V/OFF :
GND) of control ICs (1Q1 to 2Q3 of IC308,
and 2Q7 and 2Q8 of IC310 on the CP-364
board) proper?
Is power supply (anode :
+
2 V) to LED
proper?
NG
IC308 (F-2) and IC310 (F-2) defect on the
CP-364 board
NG
Defect of resistor block (on CP-365 board)
Is input signal (ON : low/OFF : high) at
I0 to I7 of IC309 (G-3) and I0 to I15 of
IC311 (G-3) on the CP-364 board proper? IC309 or IC311 defect on the CP-364 board
or soldering defect
Is LED test OK?
NG
NG
OK
LED defect in switch or soldering defect